KR19990030283A - Storage devices, data processing systems and data recording and reading methods - Google Patents

Abstract

A storage device, a data processing system, and a data recording and reading method in which area management information can be distributed and stored without affecting transmission efficiency, and compatibility with existing storage devices can be maintained despite a change in cell structure. The flash memory 21, the conversion unit 25 and the controller 26 are provided. The conversion unit 25 converts the input area management information into an area management flag corresponding to the area management information and to which extra data is added. The controller 26 causes the area management flag to be stored in the flash memory 21. The conversion unit 25 converts the area management flag read from the flash memory 21 into original area management information. The controller 26 outputs this area management information.

Description

Storage devices, data processing systems and data recording and reading methods

Field of invention

The present invention provides a storage device for storing arbitrary data, data management information for controlling this optional data, and area management information for managing the state of an area storing the data, and such a storage device. A data processing system to be used. The present invention also provides data storage for storing or reading out arbitrary data, data management information for controlling the arbitrary data, and area management information for managing the state of the area storing the data in the storage device. And a reading method.

Description of the related technology

To date, card type external storage devices (hereinafter referred to as memory cards) that use flash memory (electrically erasable and programmable read-only memory (ROM)) as recording media have been proposed as external storage devices used in electronic devices. Has been.

In such a memory card, management data as arbitrary data and auxiliary data are stored in a memory which is a recording medium. When these data and management information are transferred from a memory card to, for example, a host-side computer, the data and management information is used to correct an error data generated by a cell failure before outputting the data or management information. Is corrected using.

As the management information, information (area management information) for managing the state of the data storage area, such as information indicating whether or not the area holding data on the memory is available, is logically indicative of the sequence of stored data. It may be stored in addition to data-dependent information for managing data (data management information) such as an address.

Since such area management information is information related to an area in the memory, that is, information that is not related to data, there will be a need to rewrite the information after the data is stored, and therefore the area management information is usually independent without rewriting the data. Should be rewritten.

Also, if an error occurs, error correction is performed using a normal error correction code, and the error correction code must be rewritten each time the information is rewritten. Therefore, in order to correct an error without using an error correction code, it is preferable that the same information is stored in a state in which a plurality of bits are dispersed in the area management information.

However, if the area management information is stored in a state dispersed in a plurality of bits, the transmission data increases in length when reading data from the memory card, thus lowering the transmission efficiency. Recently, a technique for storing a plurality of bits of information in a single cell has been proposed. If the number of bits stored in one cell is increased, the number of distributed bits for correcting the error should be increased, and thus the transmission efficiency is further lowered.

In addition, if the cell structure of the memory card is changed and the information distribution scheme is changed, the status of data transmitted from the host side to the memory card, the configuration of a driver for the host side to manage the memory of the memory card, or the interface specification ( It is difficult to maintain compatibility with existing memory cards because of changes in specifications. In particular, in the case of an electronic device having a built-in driver such as a digital camera, a new memory card cannot be used because a software version upgrade method cannot be used.

Summary of the Invention

Accordingly, an object of the present invention is to provide a storage device, a data processing system and data recording and reading, in which area management information can be distributed and stored without degrading transmission efficiency and compatibility with existing storage devices can be maintained even if the cell structure is changed. To provide a way.

In one aspect of the present invention, the present invention provides storage means for storing data and area management information for managing a state of an area in which the data is stored, and input area management information corresponding to the area management information and having extra data. storage means for converting the area management flag to which (redundant data) is added or for converting the area management flag read from the storage means into original area management information, and the area management flag converted by the conversion means. And control means for reading or supplying the area management flag from the storage means to the conversion means and outputting the original area management information converted by the conversion means.

In such a storage device, the input area management information is converted into area management information having a larger number of bits than the area management information by the conversion means. The area management flag converted by the conversion means is recorded in the storage means by the control means.

In such a storage device, the area management flag read from the storage means by the control means is converted into the original area management information by the conversion means. The area management information thus converted by the conversion means is output under the control of the control means.

In this storage device, the conversion means preferably includes a conversion table in which area management information and area management flags are recorded in association with each other. The conversion means converts the input area management information into the area management flag by referring to the conversion table.

In such a storage device, the converting means preferably includes a flag discriminating circuit for discriminating the original area management information from the pattern of the area management flag read in the management information storage area of the storage means. In this case, the converting means converts the area management flag read by the storage means into the original area management information.

In another aspect, the present invention provides a storage device for storing data and area management information for managing a state of an area storing the data, and transferring the data and area management information to or from the storage device. A data processing system including a data processing apparatus for processing supplied data and area management information is provided. The storage device converts the area management information supplied from the data processing device into an area management flag corresponding to this area management information and to which extra data is added. The storage device also converts the stored area management flag into original area management information to provide the original area management information to the data processing device.

Preferably, the storage device has a conversion table in which the area management information and the area management flag are recorded in association with each other, and the input area management information is converted into the area management flag by referring to the conversion table.

Preferably, the storage device includes a flag discrimination circuit for discriminating original area management information from the pattern of the stored area management flag, and the stored area management flag is converted into area management information using this flag discrimination circuit.

Preferably, the storage device has a flash memory and converts the area management information into an area management flag of at least 3 bits per bit of information, and distributes and stores the flag in at least three cells of the flash memory.

In still another aspect, the present invention provides a method in which the area management information for managing the data and the state of the area storing the data is stored in the storage device or the data and area management information recorded in the storage device are read out from the storage device. Provided is a method for recording and reading data. The method includes converting area management information recorded in the storage device during data recording into an area management flag corresponding to the area management information and to which extra data is added, recording the converted flag in the storage device; Converting the area management flag read during the data reading into the original area management information, and outputting the thus converted area management information from the storage device.

Preferably, the storage device has a conversion table in which the area management information and the area management flag are recorded in association with each other, and the input area management information is converted into the area management flag by referring to the conversion table during data recording.

Preferably, the storage device has a flag discrimination circuit for discriminating original area management information from the pattern of the read area management flag, and the read area management flag uses this discrimination circuit during data reading to manage the original area management. Is converted to information.

Preferably, the storage device has a flash memory, and the area management information is converted into an area management flag of at least 3 bits per bit of information and distributed and recorded in at least 3 cells of the flash memory.

1 is a block diagram showing the structure of a data processing apparatus;

2 is a block diagram showing the structure of a memory card;

3 is a schematic diagram showing the structure of a storage area of a flash memory;

4 is a schematic diagram showing distributed management information.

5 is a schematic diagram illustrating an example of an area management flag.

6 is a schematic diagram showing additional management information.

7 is a schematic diagram showing the structure of aggregation management information.

8 is a schematic diagram showing another embodiment of an area management flag;

9 is a schematic diagram showing another embodiment of an area management flag;

Explanation of symbols on the main parts of the drawings

10: data processing device 11: data processing unit

12: serial interface circuit 13: register

14, 26: controller 20: memory card

21: flash memory 22: serial / parallel-parallel / serial interface circuit

25: conversion unit 27: conversion table

28 flag determination circuit 29 conversion controller

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

In the embodiment shown in Fig. 1, the present invention is a system composed of a data processing apparatus 10 which is a host side apparatus and a memory card 20 which is an external storage device connected to the data processing apparatus 10 via a serial interface ( Applies to 1).

While the system shown here is adapted to exchange data between the data processing device 10 and the memory card 20 via a serial interface, the present invention can also be applied to a system where data is exchanged through a parallel interface.

The data processing apparatus 10 used in this system 1 includes a data processing unit 11 for executing a predetermined program and a serial interface circuit 12 for exchanging data with a memory card 20 which is an external device. And a register 13 provided between the data processing unit 11 and the serial interface circuit 12 to temporarily store data transferred from the data processing unit 11, and the data processing unit 11. And a controller 14 coupled to the serial interface circuit 12 and the register 13 for controlling the processing by such devices.

If the data processing unit 10 determines that data should be stored in the memory card 20 which is an external storage device when the data processing unit 11 performs a predetermined program, the data processing unit 11 Based on the control of the controller 14, a recording command, which is storage data, management information necessary for managing the data, or control data, is recorded in the register 13.

The serial interface circuit 12 reads storage data, management information or a write command from the register 13 under the control of the jayer 14, converts them into serial data, and transmits them with the clock signal and the status signal. The management information is composed of data management information, which is information for managing data, and area management information, for managing the state of an area for recording data.

Further, if the data processing unit 11 of the data processing apparatus 10 determines that data should be read from the memory card 20 which is an external storage device in order to perform a predetermined program, the data processing unit 11 ) Writes a read command, which is control data, into a register under the control of the controller 14. The serial interface circuit 12 reads the command read from the register 13 under the control of the controller 14 and transmits it as serial data along with a clock signal and a status signal.

Data or management information transmitted from the memory card 20 in accordance with the read command is converted into parallel data by the serial interface circuit 12 and written to the register 13. The data processing unit 11 reads these predetermined data or management information from the register 13 to perform a process under the control of the controller 14.

There is no particular limitation on the data processing device used in the system of the present invention in that the data processing device used in the system of the present invention can exchange data with an external storage device such as the memory card 20. Therefore, various data processing devices such as a personal computer, a digital still camera or a digital video camera may be used.

In this system 1, the data processing device and the memory card 20 are connected to each other via a serial interface, in particular at least three data lines SCLK, STATE and DIO. That is, the data processing apparatus 10 and the memory card 20 are at least a first data line SCLK for transmitting a clock signal during data transmission, and a data signal for transmitting a status signal required for data transmission. Connected to each other by a second data line (STATE) and a third data line (DIO) for serially transferring data written to the memory card 20 or data read from the memory card 20. Data is exchanged through these data lines.

Referring to FIG. 2, the memory card 20 includes a flash memory 21 for holding predetermined data or management information on the memory, and a serial / parallel-parallel / for exchanging data with the data processing apparatus 10. A serial interface circuit (SP-PS interfacing circuit) 22. The memory card 20 is also provided between the flash memory 21 and the S / PP / S interface circuit 22 to register for temporary storage of data or management information provided from the S / PP / S interface circuit 22. And an error correction circuit 24 connected to the register 23 to correct an error based on an error correction code in the data or data management information recorded in the register 23. The memory card 20 also converts the area management information read from the register 23 into information (hereinafter referred to as the area management flag) composed of such area management information and redundant data added thereto or the flash memory 21 Conversion unit 25 for changing the area management flag read from the " The memory card 20 is also connected to the flash memory 21, the S / PP / S interface circuit 22, the register 23 and the conversion unit 25 and has a controller 26 for controlling their processing operations. It includes more.

The S / PP / S interface circuit 22 is connected to the serial interface circuit 12 of the data processing apparatus 10 via at least three data lines SCLK, STATE and DIO mentioned above, so that these data lines SCLK , STATE and DIO) to exchange data with the data processing device. In other words, the S / P-P / S interface circuit 22 converts the serial data transmitted from the serial interface circuit 12 of the data processing apparatus 10 into parallel data recorded in the register 23. In addition, the S / PP / S interface circuit 22 converts the parallel data read from the register 23 into serial data, and sends the converted serial data to the serial interface circuit 12 of the data processing apparatus 10. .

The serial data is transmitted via the first data line SCLK between the S / PP / S interface circuit 22 and the data processing device 10 and is synchronized by a clock signal transmitted from the processing device 10 at this time. Is performed. At this time, the data type of the serial data exchanged through the third data line DIO is determined by the status signal exchanged through the second data line STATE. The data type may be enumerated, for example, as data to be stored in the flash memory 21, data read from the flash memory 21 and control data for controlling the operation of the memory card 20.

If the data transmitted from the data processing apparatus 10 is control data such as a write command or a read command, the S / P-P / S interface circuit 22 supplies the control data to the controller 26.

The controller 26 controls the operation of the memory card 20 based on the control data supplied from the S / P-P / S interface circuit 22.

The register 23 temporarily stores data exchanged between the flash memory 21 and the S / P-P / S interface circuit 22.

The error correction circuit 24 adds an error correction code by the S / P-P / S interface circuit 22 to the data recorded in the register 23. The error correction circuit 24 also performs error correction processing on the data read from the flash memory 21 and written in the register 23.

The conversion unit 25 converts the area management information of the management information read from the register 23 into an area management flag, and converts the area management flag read from the flash memory 21 into the original area management information.

If data to be recorded, management information, and a recording command are transmitted from the data processing apparatus 10 to the memory card 20 as serial data, the S / PP / S interface circuit 22 converts these data into parallel data. At the same time as sending a write command to the controller 26, predetermined data and management information are written to the register 23 under the control of the controller 26.

The error correction code different from the area management information is added by the error correction circuit 24 to the predetermined data and management information recorded in the register 23 in this way.

The controller 26 reads predetermined data and management information from the register 23 and writes the read data or information to the flash memory 21 based on a write command sent from the S / PP / S interface circuit 22. do. At this time, the controller 26 first transmits the area management information of the management information read out from the register 23 to the conversion unit 25. The area management information transmitted to the conversion unit 25 is converted into an area management flag by this conversion unit 25. The controller 26 causes the area management flag converted by the conversion unit 25 to be recorded in the flash memory 21.

When the read command is transmitted from the data processing apparatus 10 to the memory card 20, the S / P-P / S interface circuit 22 transmits this read command to the controller 26.

The controller 26 reads predetermined data and management information from the flash memory 21 based on a read command sent from the S / PP / S interface circuit 22 and writes the read data or information into the register 23. To work. The controller 26 causes the area management flag sent from the flash memory 21 to be sent to the conversion unit 25. The area management flag sent to the conversion unit 25 is converted back to the original area management information by this conversion unit 25. The controller 26 causes the original area management information converted by the conversion unit 25 to be written to the register 23.

If any error exists in the data recorded in the register 23 or the data management information of the management information, it is corrected by the error correction circuit 24z0 based on the error correction code.

The S / PP / S interface circuit 22 reads predetermined data and management information from the register 23 under the control of the controller 26 and converts the read data or information into serial data transmitted to the data processing apparatus 10. It works to convert.

The above description relates to a system in which an error correction circuit 24 is provided to the memory card 20 and error correction is performed in the memory card 20. However, the present invention can be applied to a system in which the data processing apparatus includes an error correction circuit and error correction is performed by the data processing apparatus. In this case, what is exchanged between the data processing apparatus 10 and the memory card 20 is data to which an error correction code has been added.

The structure of the storage area of the flash memory 21 mounted on the memory card 20 will be described below.

The storage area of the flash memory 21 is composed of a plurality of cells which are storage units and is divided into a plurality of blocks which are data erasing units as shown in Fig. 3A. Each unique physical address is assigned to these blocks.

Each block is a data erasing unit and a minimum unit for file management. That is, the file is designed to be stored in one or more blocks and the same block is not utilized by the plurality of files.

Each block is composed of a plurality of cells, each of which stores information capable of taking two states, one and zero.

Initially, all bits in each block are set to 1 so that a bit-based change can only be made from 1 to 0. Thus, if data consisting of 1s and 0s is written to the flash memory 21, the bits for 1 are retained and at the same time the bits for 0 are changed from 1 to 0 before data writing.

If the data once written is erased in the flash memory 21, the data is initialized at once in block units to set all bits of the block to one. This erases the data written to the block all at once so that the block is again in a state that allows data writing.

Each block of the flash memory 21 is composed of a plurality of pages which are data writing or reading units, as shown in Fig. 3B. Each page represents a storage unit having a recording capacity of, for example, 512 bytes. When data is written to the flash memory 21, the data read from the register 23 in units of pages is written to the flash memory 21 in units of pages. When reading data from the flash memory 21, the data is read out page by page by the controller 25 and then transferred to the register 23.

Each page representing a data recording or reading unit has a data storage area and a management information storage area. The data storage area means an area for recording arbitrary data, and the management information storage area indicates an area for storing information (management information) necessary for management of data recorded in the data storage area.

The management information storage area has an area of 16 bytes, where the first 3 bytes are set as an overwrite area in which information can be rewritten without a batch-based initialization. The remaining 13 bytes are set to the general area for batch initialization based on the information re-proxy block.

The management information is stored in the management information storage area of each page constituting the block. In particular, as information necessary for managing blocks, so-called distributed management information is stored in the management information storage area of the first page of each block, as shown in Fig. 3C. The management information storage area of each page from page 2 of each block stores the same management information as the distributed management information stored in the management information storage area of the first page as preliminary distributed management information. However, in the management information storage area of the last page of each block, so-called additional management information that stores insufficient information only by the distributed management information is stored.

Therefore, distributed management information for managing each block is stored in the management information storage area of each block of the flash memory 21 mounted in the memory card 20. Information on whether or not the corresponding block is a leading end block of the file, or when the file is composed of a plurality of files, information indicating block association can be obtained by this distributed management information.

By collecting distributed management information of each block, the memory card 20 forms so-called collective management information as information for managing the entire flash memory 21, and collectively manages it as a file in the flash memory 21. Remember the information.

If data is exchanged between the data processing apparatus 10 and the memory card 20, the data processing apparatus 10 typically reads the collective management information from the flash memory 21 to obtain information necessary to access each block. Acquire. This eliminates the need for access to distributed management information stored in each block, thereby enabling faster data access.

Distributed management information, additional management information and aggregation management information will be discussed in more detail below.

The distributed management information is block management information stored in a 16-byte management information storage area provided on each page. This distributed management information includes one byte of possible / not possible flags, one byte of block flags, four bits of last flags, four bits of reference flags, It consists of a 1-byte management flag, a 2-byte logical address, a 2-byte concatenation flag, a 2-byte error correction code for distributed management information, and a 3-byte error correction flag. Among these flags, the enable / disable flag, the block flag, the last flag and the reference flag are stored in the overwrite area of the first 3 bytes of the management information storage area.

In the general area of 13 bytes of the management information storage area, a management flag, a logical address, a spare area, an error correction code for distributed management information, and an error correction code for data are stored. The general area of the remaining 3 bytes is set as a spare area.

The enable / disable flag indicates whether the block is in an available state or in an unavailable state. That is, if an error that cannot be recovered is generated in a block, the enable / disable flag specifies that the block is in an unavailable state.

The block flag indicates the use state of the block. In particular, the block flag indicates four states of unused, leading used, used, and minutely. Of these, unused indicates an initial state in which the block is not yet used or is already erased so that the whole has a bit of 1, indicating that data can be written immediately. Head use indicates the state in which the block is being used at the beginning of the file. Usage indicates that the block is being used outside of the beginning of the file. That is, if the block flag is used, this indicates that the block is connected to another block. A microgger indicates a state in which data recorded in a block is unnecessary. In this memory card 20, if the unnecessary data stored in the block is erased, the block flag is first set to the non-trivial state, and when there is room in the processing time, the block having its own block flag is micro-erased is erased. do. This allows the memory card 20 to make the data erase process more efficient.

The final flag is a flag indicating whether a file ends in the block, in particular, a flag indicating two states of block continuing and final block. The block continue state means that the file stored in the block does not end but continues to another block. The final block state means that the file stored in that block ends at this block.

The reference flag indicates a reference to additional management information, in particular, in two states: no reference information exists and reference information present. The state of no reference information exists indicates that no additional management information is available in the management information storage area of the last page of the block. The state of reference information present indicates that valid management information exists in the management information storage area of the last page of the block.

The management flag indicates a block attribute, such as an attribute such as a read only block or a writeable block.

The logical address represents the logical address of the block. The value of the logical address is updated as necessary, for example, when performing data rewrite. However, the value of the logical address is set such that the value of the same logical address is not owned simultaneously by a plurality of blocks.

The connection address represents a logical address of another block connected to the connection block. That is, if a file linked to the block is linked to another block, the link address indicates the value of the logical address where the rest of the file is stored.

The error correction code for distributed management information is an error correction code for data of distributed management information recorded in a management flag, a logical address, a connection address, and a spare area.

The data error correction code is an error correction code for data stored in the data storage area of the page on which the data error correction code is recorded.

The above-mentioned enable / disable flag, block flag, last flag and reference flag of the distributed management information indicate information for managing the state of the data storage area, that is, area management information. Since there is a need to rewrite the reference flag irrespective of the data, a predetermined amount of extra data of the same code as the code representing the information item is added, which is out of the object of the above-mentioned error correction code for distributed management information. The flag (area management flag) is recorded in the management information storage area.

In particular, these items of area management information are stored as area management flags in which extra data is added to the overwrite area of the management information storage area, as shown in FIG.

That is, the enable / disable flag is represented by one bit of information 1 and one bit of information 0, respectively, depending on whether the block is in an available or unavailable state. For storage in the management information storage area, the enable / disable flag is converted before storage to 1 byte of information, for example 11111111 or 0, by addition of extra data.

The block flag is represented by two bit information of 11, 10, 1, and 0, respectively, depending on whether the block is unused, headed, used, and unsigned. For storage in the management information storage area, extra data is converted into 1-byte information, for example, 1111 1111, 1111 0000, 0000 1111, 0000 0000.

The last flag is represented by one bit information of one or zero for each block last or last block. For storage in the management information storage area, the final flag is converted before storage into 4-bit information, for example 1111 or 0, by addition of extra data.

The reference flag is represented by 1 bit information of 1 or 0 respectively for no reference information or for reference information present. For storage in the management information storage area, the reference flag is converted into 4-bit information of 1111 or 0 before storage.

Since area management information, which is an area management flag to which extra data is added to the area management information, is stored in the management information storage area, even if an error occurs due to a failure of the cell holding the flag, 1 and 0 By comparing the numbers, the original area management information can be recognized.

The additional management information is information stored in the 16-byte management information storage area of the last page of the block, and includes additional information for supplementing other insufficient information.

This additional management information may include, for example, one byte enable / disable flag, one byte block flag, four bits last flag, four bits reference flag, one byte identification number, two bytes of valid data size, and additional management. It consists of an error correction code of 2 bytes for information and an error correction code of 3 bytes for data.

The enable / disable flags, block flags, final flags, reference flags and error correction codes for data are similar to those for distributed management information. The error correction code for the additional information is the same as the error correction code for the distributed management information and is used for the data recorded in the identification number, the effective data size, and the spare area except for the area management flag of the additional management information.

The identification number and the valid data size are included in the additional management information as additional information supplementing other insufficient distributed management information.

Similarly to the distributed management information, the additional management information is an area management flag with added extra data, which is an enable / disable flag, a block flag, a final flag and a reference flag, and overwrites the first 3 bytes of the management information storage area. Are memorized in the area.

In the 13-byte general area of the management information storage area, an identification number, an effective data size, an error correction code for additional management information, and an error correction code for data are recorded. The remaining 5 bytes of the general area are set as spare areas.

The identification number is information for error processing. The value of the identification number is incremented each time block data is rewritten. If some kind of error is generated and there are a plurality of blocks having the same logical address, the identification number is used to determine whether the data written in these blocks is new or old. On the other hand, an area of 1 byte is used for an identification number having a value of 0 to 255. When a new logical address is used, the value is set to 0 as an initial value. If the identification number exceeds 255, the value is reset to zero. If there are a plurality of blocks with the same logical number, the block with the smaller value of the identification number becomes valid.

The effective data size represents the size of valid data in the block. In other words, if a vacant position exists in the data storage area in the block, the effective data size represents the data size value recorded in the data storage area. At this time, the reference flag is set to the presence of reference information. If no free space exists in the data storage area of the block, the effective data size is set to Oxffff as information indicating that no free space exists in the data storage area of the block.

On the other hand, the above-mentioned distributed management information and additional management information are updated to show the latest information each time the information in the block is updated.

The set management information is information formed by collecting distributed management information of each block and stored in the flash memory 21 as a file. That is, as shown in Fig. 7, the file of the collective management information collected together with the information for the management of all the files is formed from the distributed management information based on the block and stored in the data storage area of the predetermined block. The aggregation management information may be stored in a single block or over a plurality of blocks. The data processing apparatus 10 typically obtains information for accessing each block by this set management information.

Of the management information which is information necessary for data management, the area management information is converted into an area management flag having excess data by the conversion unit 25, and the management information storage area of the flash memory 21 of the memory card 20 is converted. Is stored in the overwrite area of the management information storage area. The management information flag read out from the flash memory 21 is converted into the original area management information by the conversion unit 25, which is transferred to the data processing apparatus 10 via the register 23 and the S / PP / S interface circuit 22. Is sent.

The conversion unit 25 for converting the area management information read from the register 23 into the area management flag or for converting the area management flag read from the flash memory 21 to the original area management flag will be described in detail. .

The conversion unit 25 includes the conversion table 27, the flag determination circuit 28, and the conversion controller 29, as shown in FIG.

In the conversion table 27, area management information and area management flags are recorded in association with each other. In this conversion table 27, in relation to the enable / disable flag, 1 of the area management information and 1111 1111 of the area management flag corresponding thereto are recorded, and 0 of the area management information and the area management flag corresponding thereto are recorded. 0000 0000 is recorded.

Further, in the conversion table 27, 1111 1111 of the area management flag associated with 11 of the area management information is recorded, 1111 0000 of the area management flag associated with 10 of the area management information is recorded in relation to the block flag. 0000 1111 of the area management flag associated with 1 of the management information is recorded, and 0000 0000 of the area management flag associated with 0 of the area management information is recorded.

Further, in the conversion table 27, 0000 1111 of the area management flag associated with one of the area management information is recorded in relation to the final flag, and 0000 1111 of the area management flag associated with 0 of the area management information is recorded.

In addition, in the conversion table 27, 1111 of the area management flag associated with 1 of the area management information is recorded in relation to the reference flag, and 0 of the area management flag associated with 0 of the area management information is recorded.

When the area management information is sent to the conversion unit 25, the conversion controller 29 converts the supplied area management information with reference to the conversion table 27 into an area management flag associated with this area management information.

The flag determination circuit 28 determines the original area management information from the pattern of the area management flag read out from the flash memory 21. That is, the flag determination circuit 28 performs the original area management from the pattern of the area management flag having this error even when an error due to a cell failure or the like occurs in the area management flag recorded in the flash memory 21. Configured to determine the information.

In particular, if, in relation to the last flag, one of the area management information is stored in the memory 21 as the area management flag 1111, and an error is generated in the area management flag due to the failure of the cell, and 1111 is 1110. Suppose that is converted to 1101, 1011 or 111. In this case, the flag discrimination circuit 28 compares the number of 0's and 1's of the area management flag and determines that the information having a large number, i.e., the original area management information.

The conversion controller 29 writes the information determined by the flag determination circuit 28, which is the original area management information, into the register 23.

In the above description, the 1-bit area management information for the enable / disable flag is stored in the flash memory 21, and the 2-bit area management information for the block flag as the 1-byte area management flag. At the same time, the 1-bit area management information for the final flag is stored in the flash memory 21 as the 4-bit area management flag, and the 1-bit area management information for the reference flag is stored as the 4-bit area management flag. This relates to a case where the flash memory 21 is stored. The method of adding the extra data is not limited to this configuration, because the reason that the original area management information can be determined even when a failure occurs in the cell based on the failure rate of the cell of the flash memory 21. This is because addition of redundant data can be arbitrarily selected within.

If the cell failure rate is low, two bits of redundant data may be added to one-bit area management information, converted into three-bit area management flags, and distributed and stored in three cells. In this case, if a failure occurs in one of the three cells, the original area management information can be determined by comparing the number of zeros and ones by the flag discrimination circuit 28. However, if the number of bits of redundant data added to the area management information is increased, data reliability will increase accordingly.

The memory card 20 of the present invention includes the conversion unit 25 as described above, converts the input area management information into an area management flag in which extra data is added to this management information, and converts it into the flash memory 21. By storing, even when an error occurs in the stored area management flag due to a failure of a cell of the flash memory 21, the original area management information is corrected by correcting the error of the flag without using an error correction code. It is possible to output.

Also, in order to exchange data between the memory card 20 and the data processing apparatus 10, area management information that does not have additional redundant data, that is, original area management information is transmitted, thereby adding a problem. It does not cause deterioration of transmission efficiency. In addition, even if the method of adding extra data is changed, it is not necessary to change the structure of the data processing apparatus 10 in order to cope with such a change and to ensure interchangeability between memory cards.

The foregoing has described the bi-level flash memory in which one bit of information is stored in one cell, that is, the present invention is a multi-value type in which two or more bits of information are stored in one cell. It is also applicable to memory cards equipped with flash memory (multi-valued flash memory).

In a flash memory for storing two bits of information in a single cell, in the case of a single cell failure, two bits of error are generated. Therefore, in order to store, for example, one bit of area management information in the flash memory 21, the area management information should be converted into at least five bits of area management flags and stored in three cells. In a flash memory for storing two bits of information in a single cell, if one bit of area management information is converted into at least five bits of area management flags stored in three cells, the area management flag is held. The original area management information can be identified by the flag discrimination circuit 28 of the conversion unit 25 which compares the number of 1s and 0s of the area management flags even if one of the cells is wrong and generates an error of two bits. Can be.

In particular, when storing the area management information in the management information storage area of the flash memory for storing two bits of information in one cell, the extra data is added to the area management information and the data generated thereby is shown in FIG. As described above, it is stored as an area management flag. On the other hand, in order for the flag determination circuit 28 of the conversion unit 25 to identify original area management information, it is sufficient to convert 1 bit of area management information into a 5 bit area management flag. However, since data can be more easily processed when data is converted to even bits, the embodiment shown in Fig. 8 converts and stores one bit of area management information into a six bit or one byte of area management flag and stores it at the same time. Area management information is converted into a 12-bit area management flag and stored.

That is, 1 bit of region management information 1 of the enable / disable flag indicating that the block is in an available state is converted into 1 byte of region management flag 1111 1111 and stored in four cells, which indicates that the block is unavailable. One-bit area management information 0 of the / non-available flag is converted into one-byte area management flag 0000 0000 and stored in four cells.

On the other hand, the 2-bit area management information 11 of the block flag indicating that the block is not in use is converted into a 12-bit area management flag 111111 and 111111 and stored in 6 cells, and the 2-bit area of the block flag indicating that the block is in use. The area management information 10 is converted into a 12-bit area management flag 111111 000000 and stored in six cells. Similarly, the 2-bit area management information of the block flag indicating that the block is in use is converted into a 12-bit area management flag 000000 111111 and stored in 6 cells, and the 2-bit area of the block flag indicating that the block is microscopic. The management flag 0 is converted into a 12-bit area management flag 000000 000000 and stored in six cells.

1-bit area management information 1 of the last flag indicating that the block is in the block continuation 1 bit area management information of the last flag indicating that the block is at the end of the block is converted into a 6-bit area management flag 111111 and stored in three cells. The information 0 is converted into 6-bit area management flag 0 and stored in three cells.

The 1-bit area management information 1 of the reference flag indicating that there is no reference information is converted into a 6-bit area management flag 111111 and stored in three cells, and the 1-bit area management information 0 of the reference flag indicating the reference information exists. It is converted to a 6-bit area management flag 0 and stored in three cells.

By adding extra data to the area management information and storing the resultant signal as the area management flag, even if 111111 is changed to 111100, 110011 or 1111 due to an error due to a cell failure, the original area management information 1 is the final flag. By comparing the number of 0's and 1's may be identified by the flag discrimination circuit 28.

In this case, the area management information and the above-mentioned area management flag are recorded in the conversion table 27 in association with each other.

In addition, if the area management information is converted into the area management flag and recorded in the management information recording area, 4 bytes are used as the whole area management flag. Therefore, the first 4 bytes of the 16-byte management information recording area are set as the overwrite area.

The area management information 11 of the block flag indicating that the block is not in use is converted into a 6-bit area management flag 111111 and distributed and stored in three cells. The area management information 10 of the block flag indicating that the block is in use is a 6-bit area. It is converted into management flag 101010 and stored in three cells. On the other hand, the area management information 1 of the block flag indicating that the block is in use is converted into a 6-bit area management flag 10101 and stored in three cells, and the area management information 0 of the block flag indicating that the block is small is a 6-bit area. The management flag is converted to 0 and distributed and stored in three cells.

In this case, the flag discrimination circuit 28 recognizes a code pattern in units of 2 bits and discriminates a plurality of patterns as original area management information.

In particular, if the area management information 10 indicating that the block is the first use is changed to 6-bit area management flag 101010 and distributed and stored in three cells, and one cell fails, the area management flag 101010 is 1010, 11010, 111010. , 100010, 100110, 101110, 101000, 101001 or 101011. In this case, the flag discrimination circuit 28 recognizes the code pattern of the area management flag in units of 2 bits, and determines a plurality of 10 patterns as the original area management information.

When a block flag that is two bits of area management information is stored as an area management flag, the number of bits used can be reduced.

In the above description, the present invention has been applied to a memory card 20 that is an external device, and a system 1 including the memory card 20 and the data processing device 10. However, the present invention can be applied to a data processing apparatus having an internal memory. In this case, in order to store the area management information in the internal memory, the area management information is changed and stored in the area management flag in which extra data is added to this area management information, and when the area management flag is read from the internal memory. It is sufficient to convert the area management flag into original area management information and read it.

Claims (12)

Storage means for storing data and area management information for managing a state of an area for storing the data; Conversion means for converting the inputted area management information into an area management flag corresponding to the area management information and the extra data added thereto or converting the area management flag read from the storage means into original area management information; And The area management flag converted by the conversion means is written into the storage means, or the area management flag is read from the storage means and the read flag is supplied to the conversion means to be converted by the conversion means. And a storage means for outputting original area management information. The method of claim 1, And the conversion means includes a conversion table in which the area management information and the area management flag are recorded in association with each other, and the area management information is converted into an area management flag using this conversion table. The method of claim 1, The conversion means includes a flag discrimination circuit for discriminating original area management information from the pattern of the area management flag read out from the storage device, and the conversion means uses the flag discrimination circuit to manage area read out from the storage means. Storage device that converts flags into area management information. The method of claim 1, The storage means is a flash memory, and the converting means converts the area management information into an area management flag having at least 3 bits per bit of information, the control means wherein the area management flag is at least 3 bits of the flash memory; Memory that is distributed to and stored on. A storage device for storing area management information for managing data and a state of an area for storing the data; And A data processing device for transferring said data and area management information to said storage device or for processing data supplied from said storage device and said area management information, The storage device converts the area management information supplied from the data processing device into an area management flag corresponding to this area management information with added extra data, and the storage device also converts the stored area management flag into the original area. A data processing system converting into management information and providing the original area management information to the data processing apparatus. The method of claim 5, And the storage device has a conversion table in which the area management information and the area management flag are recorded in association with each other, and the input area management information is converted into the area management flag by referring to the conversion table. The method of claim 5, The storage device has a flag discrimination circuit for discriminating the original area management information from the pattern of the stored area management flag, and the stored area management flag is converted into the area management information using this flag discrimination circuit. Data processing system. The method of claim 5, The storage device has a flash memory, the storage device converts the area management information into an area management flag of at least 3 bits per bit of information, distributes the flag to at least 3 bits of the flash memory, and so on A data processing system which stores the flag in the cell in the activated state. Data recording and reading for recording area management information for managing data and state of an area for storing the data in a storage device or for reading the data and area management information recorded in the storage device from the storage device. In the method, Converting the area management information input to the storage device during data recording into an area management flag corresponding to the area management information and the extra data added thereto, and recording the converted flag in the storage device; And Converting the area management flag read during data reading to original area management information and outputting from the storage device. The method of claim 9, The storage device has a conversion table in which the area management information and the area management flag are recorded in association with each other, During data recording, the inputted area management information is converted into an area management flag by referring to this conversion table. The method of claim 9, The storage device includes a flag determination circuit for discriminating the original area management information from the pattern of the read area management flag, During data reading, the read area management flag is converted into the original area management information using this determination circuit. The method of claim 9, The storage device has a flash memory, wherein the area management information is converted into at least 3 bits of area management flag per bit of information and distributed to at least 3 cells of the flash memory and recorded in at least 3 cells of the flash memory. How to record and read data.